Search results for "particles and fields"
showing 10 items of 22 documents
Model discriminating power ofμ→econversion in nuclei
2009
13 pages, 12 figures, 1 table.-- PACS nrs.: 13.35.Bv; 11.30.Hv.-- ArXiv pre-print available at: http://arxiv.org/abs/0904.0957
Very Heavy Flavored Dibaryons
2020
We explore the possibility of very heavy dibaryons with three charm quarks and three beauty quarks, $bbbccc$, using a constituent model which should drive to the correct solution in the limit of hadrons made of heavy quarks. The six-body problem is treated rigorously, in particular taking into account the orbital, color and spin mixed-symmetry components of the wave function. Unlike a recent claim based on lattice QCD, no bound state is found below the lowest dissociation threshold.
K--pipi amplitudes from lattice QCD with a light charm quark.
2006
4 pages, 1 figure.-- PACS nrs.: 12.38.Gc, 13.25.Es, 11.30.Rd.-- ISI Article Identifier: 000244420700019.-- ArXiv pre-print available at: http://arxiv.org/abs/hep-ph/0607220
Improved Upper Limit on the Neutrino Mass from a Direct Kinematic Method by KATRIN
2019
We report on the neutrino mass measurement result from the first four-week science run of the Karlsruhe Tritium Neutrino experiment KATRIN in spring 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are energy analyzed by a high-resolution MAC-E filter. A fit of the integrated electron spectrum over a narrow interval around the kinematic end point at 18.57 keV gives an effective neutrino mass square value of (−1.0−1.1+0.9) eV2. From this, we derive an upper limit of 1.1 eV (90% confidence level) on the absolute mass scale of neutrinos. This value coincides with the KATRIN sensitivity. It improves upon previous mass limits from kinematic measurements by almost a …
Combination of Searches for Invisible Higgs Boson Decays with the ATLAS Experiment
2019
Dark matter particles, if sufficiently light, may be produced in decays of the Higgs boson. This Letter presents a statistical combination of searches for H → invisible decays where H is produced according to the standard model via vector boson fusion, Z(ℓℓ)H, and W/Z(had)H, all performed with the ATLAS detector using 36.1 fb⁻¹ of pp collisions at a center-of-mass energy of √s = 13 TeV at the LHC. In combination with the results at √s = 7 and 8 TeV, an exclusion limit on the H → invisible branching ratio of 0.26(0.17-0.05+0.07) at 95% confidence level is observed (expected).
Search for Magnetic Monopoles and Stable High-Electric-Charge Objects in 13 Tev Proton-Proton Collisions with the ATLAS Detector
2020
We thank CERN for the very successful operation of the LHC, aswell as the support staff fromour institutionswithout whom ATLAS could not be operated efficiently. We acknowledge the support of ANPCyT, Argentina; YerPhI, Armenia; ARC, Australia; FWF, BMWFW, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq, FAPESP, Brazil; NSERC, CFI, NRC, Canada; CERN; CONICYT, Chile; CAS, NSFC, MOST, China; COLCIENCIAS, Colombia; VSC CR, MSMT CR, MPO CR, Czech Republic; DNSRC, DNRF, Denmark; IN2P3-CNRS, CEA-DRF/IRFU, France; SRNSFG, Georgia; MPG, HGF, BMBF, Germany; GSRT, Greece; RGC, Hong Kong SAR, Hong Kong China; Benoziyo Center, ISF, Israel; INFN, Italy; JSPS, MEXT, Japan; JINR; CNRST, Morocco; NWO, Nether…
Precision measurement of the mass difference between light nuclei and anti-nuclei
2015
The measurement of the mass differences for systems bound by the strong force has reached a very high precision with protons and anti-protons. The extension of such measurement from (anti-)baryons to (anti-)nuclei allows one to probe any difference in the interactions between nucleons and anti-nucleons encoded in the (anti-)nuclei masses. This force is a remnant of the underlying strong interaction among quarks and gluons and can be described by effective theories, but cannot yet be directly derived from quantum chromodynamics. Here we report a measurement of the difference between the ratios of the mass and charge of deuterons and anti-deuterons, and $^{3}{\rm He}$ and $^3\overline{\rm He}…
Measurement of the low-energy antideuteron inelastic cross section
2020
In this Letter, we report the first measurement of the inelastic cross section for antideuteron-nucleus interactions at low particle momenta, covering a range of $0.3 \leq p < 4$ GeV/$c$. The measurement is carried out using p-Pb collisions at a center-of-mass energy per nucleon-nucleon pair of $\sqrt{s_{\rm{NN}}}$ = 5.02 TeV, recorded with the ALICE detector at the CERN LHC and utilizing the detector material as an absorber for antideuterons and antiprotons. The extracted raw primary antiparticle-to-particle ratios are compared to the results from detailed ALICE simulations based on the GEANT4 toolkit for the propagation of antiparticles through the detector material. The analysis of th…
Measurement of the Fluctuations in the Number of Muons in Extensive Air Showers with the Pierre Auger Observatory
2021
The successful installation, commissioning, and operation of the Pierre Auger Observatory would not have been possible without the strong commitment and effort from the technical and administrative staff in Malargue. We are very grateful to the following agencies and organizations for financial support: Argentina-Comision Nacional de Energia Atomica, Agencia Nacional de Promocion Cientifica y Tecnologica (ANPCyT), Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET), Gobierno de la Provincia de Mendoza, Municipalidad de Malargue, NDM Holdings and Valle Las Lenas; in gratitude for their continuing cooperation over land access; Australia-the Australian Research Council; Brazil…
Search for Electron Antineutrino Appearance in a Long-baseline Muon Antineutrino Beam
2020
Electron antineutrino appearance is measured by the T2K experiment in an accelerator-produced antineutrino beam, using additional neutrino beam operation to constrain parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. T2K observes 15 candidate electron antineutrino events with a background expectation of 9.3 events. Including information from the kinematic distribution of observed events, the hypothesis of no electron antineutrino appearance is disfavored with a significance of 2.40 σ and no discrepancy between data and PMNS predictions is found. A complementary analysis that introduces an additional free parameter which allows non-PMNS values of electron neutrino and a…